I can see all 320GB in windows. When I use WBFS Manager 3.01 to format it it formats it in a couple of seconds. I can see the 320GB at the bottom (actually 298GB now).

When I add around 10/11 games it goes well. WHen I try to add the 12th game it looks like it adds it correctly. I get a message saying "completed adding entries". When I press OK however I get a message saying "error occurred while loading drive. Make sure the drive is not in use or open and that it has been formatted to WBFS format". After that I am not able to access the drive anymore. I have to pull out the USB cable and plug it back in.

Strangely I keep sitting around some virtual 23/24GB limit (meaning there are already 10 games on the drive). It looks like everything I try to add around the 23-26GB range gives me this error.

I tried different PC's, different USB ports but same error is happening.